Hydraulic turbine.



A. PFAU.

HYDRAUUC TURBNE.

MPUCAHGN mm ra.17.1913.

Patented Sept. 12, 1916.

2 SHEETS-SHUT I.

WI'f-NEEEES- INVENTEJ'R- @126 via.

A. PFAU.

HYDRAULQC TURBINE.

Armcmcw mu) FEB, 11. M13.

1. 1 97,76 1 men ted Sept. 12, 1916 Z SHEET$-$HEET 2- R mm INVE NTDR.

ATTEI NEZY.

'uni'rs STATES ATENT OFFICE.

ARNOLD PFAU, or MILWAUKEE, Wisconsin, ASSIGNOR, BY MESNE ASSIGNMENTS, 'ro ALLIs-cHALMERs MANUFACTURING COMPANY, A CORPORATION OF DE A RE.

HYDRAULIC TURBINE.

Specification of Letters Patent.

'Paten'tegisept. 12, 1916.

Application filed February 17, 1913. Serial No. 749,538.

To all whom it may concern Be it known that I, ARNOLD PFAU, a citizen of the Republic of Switzerland, residing at Milwaukee, in the county of Milwaukee and State of Wisconsin, have invented a certain new and useful Improvement in Hydraulic Turbines, of which the following is a specification.

This invention relates to improvements in the construction of hydraulic turbines, and more particularly to improvements in the construction of guide vanes and runners for turbines of the Francis type.

An object of the invention is to provide a hydraulic turbine which is simple in construction, efficient in operation, and in which the cost per unit of power produced is reducedto a minimum;

In hydro-electric installations operating under low loads, it is desirable to produce the. maximum power with a runner of minimum size in order that'the power house cost may be reduced to a minimum. R is also desirable to operate the turbines and generators driven thereby at high speed so that the cost of the electrical apparatus maybe reduced to a minimum; With the present invention these desirable features are 0btained byso constructing the turbine that the maximum amount of motive fluid may be effectively passed through a runner of minimum diameter, thereby producing the maximum power at the desired high speed.

A clear conception of an embodiment of the invention may be had by referring to the drawings accompanying and forming a part of this specification, in which like reference ner thereof. Fig. 3 is an enlarged top view of several of the guide vanes, showing same in both full open and closed positions. Figs. 4 and 5 are side and top elevationsrespectively, of a prism having the general shape of an ordinary guide vane.

, Figs. 6 and 7 are side and top elevations of a prism similar to that disclosed in Fi s. 4 and 5, the prism having been distorte by twisting. Figs. 8 and 9 are side and top elevatigns respectively, of a prism similar'to that disclosed in Figs. 6 and 7, the prism having been additionally distorted by skewing.

The turbine runner consists of a rotor 4 having secured thereto a circular series of outwardly flaring buckets 1, the upper ends of the leading-edges of which are nearer the turbine axis than the lower ends. The rotor 4 is secured to the turbine shaft 2, which is supported by a suitable bearing 12,

fixed to the upper casing 5 of'the turbine;

The lower casing 6 of the turbine is supported above the draft tube 3, which connects with the tail-race in the usual manner. The guide vanes 8 span the inlet opening which has walls perpendicular to the turbine axis and isformed between the upper I and lower casings 5, 6. The vanes 8 control the extent of opening and the direction of flow of the inlet to the turbine. The spent motive fluid. upon leaving the turbine runner is discharged axially through the draft tube 3.

The guide vanes 8 are pivoted to the upper casing 5 by means of thepins 9, and to the lower casing 6 by means of pins 11. The

pins 9, ll, may either be inde )endenft pinsor they may be opposite ends 0 the same pins which pass through, the guide vanes 8. The

guide vane adjusting ring 7 is mounted upon a bearing formed on the lower casing 6'eon-. centric with the turbine runner. The ring 7 is angularly shiftable about the turbine axis by means of a gate controlling shaft 13 which is connected with the ring 7 throu'g'h a bell crank 15 and links 14. The shaft13 is supported in a suitable bearing formed in the bracket 16. The guide vanes 8 are provided with projecting pins 10 at their-lowerend's which engage the slots 18 formed in the ring 7. As the ring 7 is shifted angularly about the turbine axis, the pins 10 move along the slots 18 and cause the guide vanes 8 to assume different angular positions relative to the turbine runner.

The formation of the-individual guide vanes willibe readily understood by referring to Figs. 4 to 9 inclusive, which disclose three steps in the developme t of one of the vanes. Figs. 4 and 5 discl sea prism 21 having the general'shape of an ordinary guide vane in which the axis 25 is perpcn chcu-lar to its upper and lower surfaces 2-4, 26, and lll; wlll()h the leading and trailing edges 28, 27, respectively, are also perpendicula'r to the end surfaces and. parallel to the axis 25. The aXis 25 and edges 28, 27

of the vane' 21 are parallel to the turbine axis. produced by distorting the vane 21 by rela- In Figs-(3 and 7;,the vane 22 has been tive twisting ofthe upper and lower portions about the axis-25; The'axis 25 of the. .vane 22 is still perpendicular to the surfaces 24,- 2(i,'hnt the leading and trailing edges 28', 27, have been inclinedrelatively to'the "end'sur fa'ces and relatively to the. turbine a\'is,.-"Tlie tWlSlZlIl" of-the vane has produced warped gui in-g surfaces and has dis-. 'tortedthe trailing, end of the vane transversely-relatively to the-fluid passage past the vane. in Figs. 8 and 9, tlie 'va ne, .5 has he'en'produced hy'relatively shifting the up per and lower portion of the vane :22 in a direction 'along'the adjacent fluid passage and intheidirection of low of the lluid past the vane, causing th axis 25 to assume. an

inclined position relatively to the end sin and projectionswhich \vould tend to on desirably distribute the ilou of vat'er past circle of tangency-ofzthe lowerqiii'rtion off vanes. 'lhe faces 24,, 2b. The vane. 23 besides being; warped, has been skeived in a direetiini along the adjacent fluid passage, and is substantially like the vanes 8 except. that the latter have been dressed to eliminateabruptedges thefvane. V

circle which is eonsiderably smaller than-the the guiding surfaces of the .propcr direction of thewrespective portii'ms of the guiding surface of each vane 8 is sccm'ed by warpingtli'e .i'a'n'e guiding sin:- face to correspond with tl'rel direction of the inlet edges of the buckets L As the diameter of the bucket inlet Or leadilltf "yes is eonsiderably less at. the upper ei :of the/turbineithan at the lower end thereof, it should he notedlhat by warping the'guide vane surfau-s'the inlet angle a of the stream f motive llmd entering between two success ve,

constant relative to the tangents 'to' the inlet.

The upper portion of theguidiiig surface v of each ofthe vanes Sis formedtangent-to a maintain the inlet diameter of the'runner as large. as possible, the guide vanes 8, be-' sides being warpedor distorted transversely to the direction of flow of. the fluid, are

, skewed or given an oblique shape by distor- .\'anes' in closed position.

.sides respectively. The contact strips ifill are tion in a direction along the adjacent fluid passages. The. degree. of skewing of the guide vanes 8 is determined by the desired amount f clearance volume. It is not desirable to reduce the clearance volume beyond a certain amount, such amount being necessary to insure smooth entry of the m0- tire lluid to the turbine runner for all angular positions of the guide vanes 8. The :'-;ke. \vin; of the guide'va'nes 8 in a' direction along the adjacentfluidpassage besides redu'ein; Uri-clearance volume, permits reduc tion of'the diameter of the casing 5 so. that a relativelysmall inlet flame may be-utiliY-ed without in'ulesirably restricting; the turbine inlet passage.

It should he noted that as a result of the distortifln of the-vanes 8 in a direction relative to their axes of swing, the inner edgesthereof would not coact properlyin closed position without provision for in suring such closing. The warping ofthe ranesS partially insures suclrcontzwt of'the In order to absolutely insure perfect Contact" ofadjacent vanes S in closed position, the vanesare pro long the ad acent [hud' passage and at an angle iisi vided with parallel ina( :'l'ii-'ne d conta'ct' sur-i faces or strips 20: at their trailingedges and formed as planesxwhich are. parallel to the ii isure' contact along the; entire. vanes in edges of the, buckets tailing the. entire closed position. It \vill be noted that due to the \varpirr; ofthe guide-surfaced o'fthe vanes, the straight line elements foi lll 'in" the strips 3!! are not-paralle| to theaia-Iie hXes but slope. forward. see Fig. l.

From this descriptionand disclosure .it will be readily seen that 'by skewing the guide vanes H in a direction alone the adja rent lluid passages and warping! the guiding 'snrl'are lo properl)- direct the entering m'o tire lluid. the runner may he. so ili rained as to provide an ellirieut minimum s .ed runner capa le of lIl(Hll!(.flH maximum.pout-i 'lhe guide vanes- 18 are capable of admittillffia large amount of motive lluid to the turbine buckets l in the most ellieiert manner. thereby permitting an increase 'of speed which results in the desired reduction in the cost of the turlurgenerators. I

'lhe terms upper and lou'er'are in this specificati n merely to designate di-' rerlion with reference to the particular form nf iiillilllt. disclosed, hutsit is'not desired to limit the invention to such specific constru ti n or design. it is not desired to be'l'im'ited to-the exact details of construction shown and described,

employed axis of rotation-of the. 'v'anesl'l in'forder to f lt should he. understood that 

